WALNUT CREEK -- The family of a hairdresser killed by Walnut Creek police last month is seeking $15 million in a wrongful-death suit filed against four members of the police department, alleging the 22-year-old man was shot after officers tripped and fell over one another.

Anthony Banta Jr. was killed Dec. 27 when officers say he charged them with a knife after a fight with his roommate in their Creekside Drive apartment. A lawsuit filed Jan. 24 in U.S. District Court in San Francisco maintains the altercation had ended by the time police arrived and that Banta was not armed. The lawsuit says that one officer fired in a panic after reacting to the other officers tripping and falling behind him, and that other officers also opened fire.